In a small bowl, mix together your mayonnaise, and sour cream. Make sure the two are completely combined and then add half of the chives, cheese, and pepper. Taste mixture to see if you prefer some salt. (I usually add a dash or two.) Let chill in fridge for a bit. Meanwhile, peel and cube your potatoes in to bite size pieces. Put in a large pot, cover with water, and boil until fork tender. About 20 minutes. *You need to keep an eye on them. If they cook too long you’ll end up with more of a mashed potato consistency when you mix them with the sauce.

When potatoes are ready, drain and let cool just a bit. *Let them cool a lot if you plan to serve chilled. Put potatoes in a large bowl or dish and combine with sour cream mixture. Fold in most of your crumbled bacon. Top with remaining half of chives and remaining crumbled bacon.

2) Layer 1/2 of the potatoes into bottom of the prepared casserole dish. Top with the onion slices, and add the remaining potatoes. Season with salt and pepper to taste.

3) In a medium-size saucepan, melt butter over medium heat. Mix in the flour and salt, and stir constantly with a whisk for one minute. Stir in milk. Cook until mixture has thickened. Stir in cheese all at once, and continue stirring until melted, about 30 to 60 seconds. Pour cheese over the potatoes, and cover the dish with aluminum foil.